时域色散选通光谱分析技术  

Time dispersion gated spectrum analysis technology

作　　者：靳致远 章振 夏海云 胡佳栋 余赛芬 陈逸翔 夏秋炜 JIN Zhiyuan;ZHANG Zhen;XIA Haiyun;HU Jiadong;YU Saifen;CHEN Yixiang;XIA Qiuwei(School of Atmospheric Physics,Nanjing University of Information Science&Technology,Nanjing 210044,China;National Center of Carbon Metrology(Fujian),Nanping 353011,China)

机构地区：[1]南京信息工程大学大学大气物理学院,江苏南京210044 [2]国家碳计量中心(福建),福建南平353011

出　　处：《红外与激光工程》2024年第7期251-259,共9页Infrared and Laser Engineering

基　　金：国家重点研发计划项目(2022YFF0606400);国家自然科学基金项目(42305147);江苏省基础研究计划自然科学基金项目(BK20230428)。

摘　　要：光频域的光谱分析技术已在分子原子光谱学中发挥了重要作用,但仍存在频率扫描慢、锁定复杂等问题。基于此,提出了一种基于时域的光谱选通和扫描方法,具有光谱分辨率高、扫描速度快和无机械运动元件的优点。飞秒时域拉伸技术作为一种超快探测手段,能够将飞秒脉冲展宽至纳秒,并实现光谱信息至时域信息的实时映射。在时域中使用皮秒级脉冲调制展宽后的纳秒脉冲,可选通出特定光谱。选通后,调节皮秒脉冲的延时便可完成光谱的扫描。通过51次延时选通测量氰化氢气体的2ν3旋转振动带P10吸收线,验证了该时域色散选通法的光谱分析能力。单次测量的累计时间为5μs,230 ps选通脉冲宽度和56 ps扫描间隔对应的光谱分辨率和光谱扫描间隔分别为6.2 GHz和1.5 GHz,与色散光谱仪直接测量对比的误差标准差为0.0065,最大偏差的百分比为1.54%。未来通过降低选通脉冲宽度至30ps和提高脉冲扫描速度,该光谱分析技术可达到0.8 GHz的光谱分辨率和千赫兹以上的光谱扫描速度。Objective Modern spectroscopic analysis technology has developed into a discipline that studies the absorption,emission or scattering spectra of substances, and has played a key role in many fields. In the field of spectroscopy,spectral scanning is performed by adjusting slits in spectroscopic instruments, but there are problems such as wavelength drift and frequency instability caused by mechanical movement. The stability of mechanical movement and the performance of spectroscopic elements gradually limit the development of spectrometers. In the field of gas detection, with the development of laser technology, gas detection lidar based on optical frequency comb locking can achieve high-resolution remote sensing of various gas spectra. The optical frequency comb reference locking scheme has the advantages of high stability and wide tuning range, but it also faces the problems of complex system and long tuning process. In summary, whether it is adjusting the slit or the laser cavity, the current spectrum analysis technology operates and detects the spectrum in the optical frequency.Methods This paper proposes a spectral analysis technology based on time dispersion gating to achieve fast and high-resolution spectral analysis without locking. First, a large amount of dispersion is introduced through time stretching technology to stretch femtosecond laser pulses to nanosecond pulses, and achieve one-to-one mapping between spectrum and time. Secondly, picosecond pulses are used in the time to modulate the time stretched ns pulses to achieve selective passage of light frequency, similar to the role of slits in spatial dispersion spectrometers. Finally, spectrum scanning is achieved by adjusting the delay of the ps pulse. Since the ps pulse is generated by electronic devices and loaded into the modulator, the ps pulse width and delay are controlled by the electrical signal generator. Its one-to-one corresponding spectral resolution and scanning speed can break through the limits of traditional spectral analysis technolo

关 键 词：光谱分析 时域拉伸 频率选通 频率扫描 

分 类 号：O433.4[机械工程—光学工程]